System and method for attaching a surgical instrument to a patient&#39;s bone

ABSTRACT

A surgical instrument system and method of use is disclosed. The system includes a bone fixation pin and a surgical instrument configured for use with the bone fixation pin. The surgical instrument includes a sheath extending over the distal end of an elongated shaft and a locking mechanism operable to permit selectively movement of the elongated shaft along the longitudinal axis relative to the sheath.

This application is a divisional application and claims priority to U.S.patent application Ser. No. 14/674,757, now U.S. Pat. No. 10,603,094,which was filed on Mar. 31, 2015, the entirety of which is expresslyincorporated herein by reference.

TECHNICAL FIELD

The present disclosure relates generally to orthopaedic surgicalinstruments and, more particularly, to surgical instruments used toresect a patient's bone.

BACKGROUND

Joint arthroplasty is a well-known surgical procedure by which adiseased and/or damaged natural joint is replaced by a prosthetic joint.Typical artificial joints include knee prostheses, hip prostheses,shoulder prostheses, ankle prostheses, and wrist prostheses, amongothers. To facilitate the replacement of the natural joint with theprosthesis, orthopaedic surgeons use a variety of orthopaedic surgicalinstruments such as, for example, saws, drills, reamers, rasps,broaches, cutting blocks, drill guides, milling guides, and othersurgical instruments.

SUMMARY

According to one aspect of the disclosure, a surgical instrument systemis disclosed. The surgical instrument system comprises a bone fixationpin including a head and a shaft extending from the head to a distal endhaving a plurality of threads defined therein, and a surgical instrumentconfigured for use with the bone fixation pin. The surgical instrumentcomprises an elongated shaft defining a longitudinal axis extendingthrough its proximal end and its distal end, a socket defined in thedistal end of the elongated shaft that is sized to receive the head ofthe bone fixation pin, a shank extending outwardly from the proximal endof the elongated shaft along the longitudinal axis that is configured toengage a surgical drill, a sheath extending over the distal end of theelongated shaft, and a locking mechanism coupled to the elongated shaft.The locking mechanism is operable to permit selectively movement of theelongated shaft along the longitudinal axis relative to the sheathbetween a position in which over-turning or over-torqueing the bonefixation pin is prevented and another position in which full torque maybe applied to the bone fixation pin for final tightening or removal ofthe pin from the bone. In that way, the torque applied to the bonefixation pin may be controlled.

In some embodiments, the locking mechanism may include a locking tabthat is moveable between a locked position in which the locking tab ispositioned in an opening of the sheath to prevent movement of theelongated shaft and an unlocked position in which the locking tab isspaced apart from the opening to permit movement of the elongated shaft.

In some embodiments, the locking mechanism may include a body that ispositioned in a slot defined in the elongated shaft, and the locking tabmay extend outwardly from the body. Additionally, in some embodiments,the body may include a biasing element that biases the locking tab inthe locked position. In some embodiments, the slot defined in theelongated shaft may extend longitudinally through the elongated shaft.

In some embodiments, the body may include a first end engaged with aninner surface of the sheath. When the locking tab is in the lockedposition, a second end of the body may be engaged with a distal-facingsurface of the elongated shaft. When the locking tab is in the unlockedposition, the second end of the body may be disengaged from thedistal-facing surface of the elongated shaft.

In some embodiments, the first end of the body may be received in agroove defined in the inner surface of the sheath. In some embodiments,the sheath may include a distal opening defined in its distal end and acentral passageway that extends inwardly from the distal opening. Theelongated shaft may be positioned in the central passageway of thesheath. When the elongated shaft is moved in a first direction relativeto the sheath, the distal end of the elongated shaft may be moved alongthe central passageway toward the distal end of the sheath.

In some embodiments, the head of the bone fixation pin may extend from aproximal end of the bone fixation pin to a distal edge. The threads ofthe shaft may extend from the distal end to a proximal edge, and a firstdistance may be defined between the distal edge of the head and theproximal edge of the threads. When the elongated shaft is located in afirst position relative to the sheath, a second distance may be definedbetween the distal opening of the sheath and the distal end of theelongated shaft. The second distance may be greater than the firstdistance such that a number of the threads of the bone fixation pin arepositioned in the central passageway of the sheath when the head of thebone fixation pin is fully seated in the socket of the elongated shaft.

In some embodiments, the elongated shaft may be moveable to a secondposition in which a third distance is defined between the opening of thesheath and the distal end of the elongated shaft. The third distance maybe less than the first distance.

In some embodiments, the locking mechanism may be biased in a lockedposition in which the elongated shaft is prevented from moving relativeto the sheath when the elongated shaft is in the first position.Additionally, the locking mechanism may be in an unlocked position inwhich the elongated shaft is permitted to move relative to the sheathwhen the elongated shaft is the second position.

Additionally, in some embodiments, the elongated shaft may include apair of tabs extending outwardly from its proximal end and the sheathincludes a pair of guide slots that receive the pair of tabs. The guideslots and the tabs may cooperate to prevent rotational movement aboutthe longitudinal axis. In some embodiments, the socket and the head ofthe bone fixation pin may have corresponding triangular cross sections.

According to another aspect, a method of attaching a surgical instrumentto a patient's bone is disclosed. The method comprises positioning thesurgical instrument in a desired location relative to the patient'sbone, inserting a head of a bone fixation pin through a distal openingof a fixation pin driver into a socket defined in an elongated shaft ofthe fixation pin driver, positioning a threaded distal end of the bonefixation pin in a guide hole defined in the surgical instrument,rotating the fixation pin driver to thread the bone fixation pin intothe patient's bone, engaging a distal end of the fixation pin driverwith an outer surface of the surgical instrument, operating a lockingmechanism of the fixation pin driver to release the elongated shaft ofthe fixation pin driver for movement relative to an outer sheath of thefixation pin driver that includes the distal end of the driver, androtating the fixation pin driver and advancing the socket of thefixation pin driver toward the distal opening of the fixation pin driverto further thread the bone fixation pin into the patient's bone.

In some embodiments, the method may further comprise securing a proximalend of the elongated shaft to a surgical drill. In some embodiments, thesurgical instrument may be a cutting guide block.

In some embodiments, the method may further comprise engaging an annularflange of the bone fixation pin with the outer surface of the surgicalinstrument after advancing the socket of the fixation pin driver towardthe distal opening of the fixation pin driver. Additionally, in someembodiments, the method may further comprise moving the socket of thefixation pin driver away the distal opening of a fixation pin driveruntil a biasing element causes the locking mechanism to engage the outersheath and prevent movement of the elongated shaft.

According to another aspect, a surgical instrument system comprises abone fixation pin including a head extending from a proximal end of thebone fixation pin to a distal edge, and a shaft extending from the headto a distal end having a plurality of threads defined therein thatextend from the distal end to a proximal edge. The system also includesa surgical instrument configured for use with the bone fixation pin. Thesurgical instrument comprises a socket sized to receive the head of thebone fixation pin and a sheath extending over the socket to a distalend. A first distance is defined between the distal edge of the head andthe proximal edge of the threads of the bone fixation pin, and thesocket is moveable between a plurality of positions relative to thesheath. The plurality of positions includes a first position in which asecond distance is defined between the distal end of the sheath and thesocket such that a number of the threads of the bone fixation pin arepositioned in the sheath when the head of the bone fixation pin is fullyseated in the socket. In some embodiments, the socket may be moveable toa second position in which a third distance is defined between thedistal end of the sheath and the socket. The third distance may be lessthan the first distance.

BRIEF DESCRIPTION OF THE DRAWINGS

The detailed description particularly refers to the following figures,in which:

FIG. 1 is a perspective view of a surgical instrument system forattaching a surgical instrument to a patient's bone;

FIG. 2 is an elevation view of a distal end of a surgical instrument ofthe system of FIG. 1;

FIG. 3 is a side elevation view of the surgical instrument of FIG. 2;

FIG. 4 is a side elevation view similar to FIG. 3;

FIG. 5 is an exploded perspective view of the surgical instrument ofFIG. 2;

FIGS. 6 and 6A are cross section views of the surgical instrument takenalong the line 6-6 in FIG. 3, with FIG. 6A showing a pin with thesurgical instrument;

FIGS. 7 and 7A are cross section views of the surgical instrument takenalong the line 7-7 in FIG. 4, with FIG. 7A showing a pin with thesurgical instrument;

FIG. 8 is a perspective view of a cutting block positioned on apatient's bone and a bone fixation pin of the surgical instrument systemof FIG. 1;

FIG. 9 is a perspective view similar to FIG. 8 showing the surgicalinstrument system of FIG. 1 used to secure the cutting block to thepatient's bone; and

FIG. 10 is a perspective view similar to FIG. 8 showing the cuttingblock attached to the patient's bone with a pair of bone fixation pins.

DETAILED DESCRIPTION OF THE DRAWINGS

While the concepts of the present disclosure are susceptible to variousmodifications and alternative forms, specific exemplary embodimentsthereof have been shown by way of example in the drawings and willherein be described in detail. It should be understood, however, thatthere is no intent to limit the concepts of the present disclosure tothe particular forms disclosed, but on the contrary, the intention is tocover all modifications, equivalents, and alternatives falling withinthe spirit and scope of the invention as defined by the appended claims.

Terms representing anatomical references, such as anterior, posterior,medial, lateral, superior, inferior, etcetera, may be used throughoutthe specification in reference to the orthopaedic implants or prosthesesand surgical instruments described herein as well as in reference to thepatient's natural anatomy. Such terms have well-understood meanings inboth the study of anatomy and the field of orthopaedics. Use of suchanatomical reference terms in the written description and claims isintended to be consistent with their well-understood meanings unlessnoted otherwise.

Referring to FIG. 1, a surgical instrument system 10 for attaching asurgical instrument to a patient's bone is shown. The system 10 includesa bone fixation pin 12 and a fixation pin driver 14 configured to beattached to the head 16 of the fixation pin 12. As described in greaterdetail below, the driver 14 is operable to control the torque applied tothe fixation pin 12.

The fixation pin 12 includes an elongated shaft 18 that extends distallyfrom the head 16 to a distal tip 20 of the pin 12. In the illustrativeembodiment, the pin 12 is formed as a single, monolithic component froma metallic material such as, for example, stainless steel. In otherembodiments, the head 16 and shaft 18, for example, might be formed asseparate components. A plurality of threads 22 are defined in theelongated shaft 18 and extend from the distal tip 20 to a proximal edge24. The threads 22 are configured to grip the patient's bone to hold thepin 12 (hence the surgical instrument) in position on the bone.

The head 16 of the fixation pin 12 is positioned at a proximal end 26 ofthe pin 12. The head 16 includes a number of substantially planarsurfaces 28 that extend distally from the proximal end 26 to a distaledge 30. In the illustrative embodiment, the surfaces 28 define agenerally triangular-shape; in other embodiments, the surfaces 28 maydefine, for example, a generally square shape.

The elongated shaft 18 includes a substantially smooth surface 32 thatconnects the proximal edge 24 of the threads 22 to the distal edge 30 ofthe head 16. The fixation pin 12 also includes an annular flange 34 thatextends outwardly from the surface 32. As shown in FIG. 1, a distance 36is defined between the distal edge 30 and the proximal edge 24.

The driver 14 includes a sheath 40 that extends over an elongated shaft42. The shaft 42 is moveable relative to the sheath 40, but the driver14 includes a locking mechanism 44 operable to fix the sheath 40 and theshaft 42 in position relative to one another. The shaft 42 has a driveshank 46 formed at its proximal end 48. The shank 46 is configured toengage a surgical drill or other rotary tool operable to rotate thedriver 14 about its longitudinal axis 50. As shown in FIG. 1, thelongitudinal axis 50 extends through the proximal end 48 of the shaft 42and the distal end 52 of the sheath 40.

An opening 54 is defined in the distal end 52 of the sheath 40, and acylindrical inner wall 56 extends inwardly from the opening 54. Theinner wall 56 defines a central passageway 58 that extends through thedistal end 52 and opposite proximal end 60 of the sheath 40. Theelongated shaft 42 extends outwardly from the proximal end 60 of thesheath 40 to its proximal end 48.

As shown in FIG. 2, the distal end 62 of the elongated shaft 42 ispositioned in the central passageway 58. A socket 64 sized to receivethe head 16 of the fixation pin 12 is defined in the distal end 62 ofthe shaft 42. The socket 64 has a number of substantially planarsurfaces 66 that extend inwardly from an annular beveled surface 68. Thesurfaces 66 correspond in shape and arrangement to the surfaces 28 ofthe head 16 such that the head 16 may be snuggly in the socket 64. Thesocket 64 is sized so that the head 16 fully seats in the socket 64,with the annular flange 34 of the pin 12 engaged with the distal end 62of the elongated shaft 42.

As described above, the shaft 42 is moveable relative to the sheath 40.As shown in FIGS. 3 and 4, the shaft 42 is moveable between acontrolled-torque position 70 (see FIG. 3) and a full torque position 72(see FIG. 4). In the controlled-torque position 70, the distal flange 74of the shank 46 is spaced apart from the proximal end 60 of the sheath40, and the socket 64 is spaced inwardly from the distal opening 54 ofthe sheath 40. In the full torque position 72, the distal flange 74 ofthe shank 46 is engaged with the proximal end 60 of the sheath 40.Additionally, the socket 64 is positioned adjacent the distal opening 54of the sheath 40.

In the illustrative embodiment, the locking mechanism 44 includes alocking tab 76 that is configured to be received in a slot 78 defined inthe sheath 40 when the shaft 42 is in a controlled-torque position 70.The engagement between the locking tab 76 and the sheath 40 fixes thesheath 40 and the shaft 42 in position relative to one another, asdescribed in greater detail below.

Referring now to FIG. 5, the sheath 40, shaft 42, and locking mechanism44 are shown in greater detail. In the illustrative embodiment, thesheath 40 is an assembly of two components 80, 82. It should beappreciated that in other embodiments the sheath 40 may be formed as asingle monolithic component. The component 80 is positioned distally anddefines the distal end 52 of the sheath 40. The other component 82includes the proximal end 60 of the sheath 40. A pair of flanges 84extend distally from the component 82 and are configured to engage acorresponding pair of slots 86 defined in the component 80 to secure thecomponents 80, 82 and assemble the sheath 40.

The proximal component 82 includes a substantially planar surface 88,and a generally rectangular opening 90 is defined in the surface 88. Anumber of inner walls 92 extend inwardly from the opening 90 to definethe locking slot 78 described above. As shown in FIG. 5, the lockingslot 78 opens into the central passageway 58, which extends through boththe components 80, 82 of the sheath 40.

As described above, the elongated shaft 42 has a distal end 62 that ispositioned in the central passageway 58 of the sheath 40. Asubstantially cylindrical surface 100 extends from the distal end 62 tothe drive shank 46 formed at the proximal end 48 of the shaft 42. In theillustrative embodiment, a pair of tabs 102 extends outwardly from thesurface 100 near the drive shank 46. Each tab 102 is received in a guideslot or groove 104 defined in the inner wall 56 of the proximalcomponent 82. The tabs 102 and grooves 104 cooperate to guide therelative movement of the shaft 42 and sheath 40 and prevent relativerotation between the shaft 42 and the sheath 40.

The shaft 42 has a longitudinal opening 110 defined in the cylindricalsurface 100. A number of inner walls 112 extend inwardly from theopening 110 to another longitudinal opening 114 defined in the oppositeside of the surface 100 to define a slot 116 extending through the shaft42, as shown in FIG. 6. The walls 112 further cooperate to define aninner chamber 118 positioned proximal of the slot 116. The slot 116 andinner chamber 118 are sized to receive the lever 120 of the lockingmechanism 44.

Returning to FIG. 5, the locking mechanism 44 has a lever 120 and thelocking tab 76 described above. The lever 120 extends from an end 122that engages the sheath 40 to another lever end 124 that engages theelongated shaft 42. The lever 120 includes an arm 126 that extends fromthe lever end 122 and is joined at its opposite end to a body 128. Thebody 128 connects the arm 126 to another arm 130 that extends from thelever end 124. The locking tab 76 extends outwardly from the connectingbody 128. In the illustrative embodiment, the lever 120 and locking tab76 are formed as a single monolithic component from a resilient materialsuch as, for example, spring steel.

As shown in FIG. 6, the arm 126 has a lip 132 formed at the lever end122 that is received in a groove 134 defined in the inner wall 56 of theproximal component 82 of the sheath 40. The arm 130 has a substantiallyplanar or flat surface 136 at the opposite lever end 124, which isconfigured to engage a distal-facing surface 138 of the elongated shaft42.

In use, the elongated shaft 42 of the fixation pin driver 14 ispositioned in the controlled-torque position 70 shown in FIGS. 3 and 6.In that position, the surface 136 of the locking mechanism lever 120 isengaged with the distal-facing surface 138 of the elongated shaft 42 andthe locking tab 76 is positioned in the slot 78 defined in the sheath40. As shown in FIG. 6, the distal end 62 of the elongated shaft 42 (andhence the socket 64) is spaced apart from the distal opening 54 of thesheath 40 such that a distance 140 is defined between the opening 54 andthe distal end 62 and socket 64 of the elongated shaft 42.

A user may load a bone fixation pin 12 into the driver 14 by aligningthe head 16 of the pin 12 with the distal opening 54 of the sheath 40.The user may then advance the head 16 of the pin 12 into the distalopening 54, along the central passageway 58, and into the socket 64 ofthe elongated shaft 42. As described above, the annular flange 34 of thepin 12 engages the distal end 62 of the elongated shaft 42 when the head16 is fully seated in the socket 64. With the head 16 fully seated inthe socket 64, a number of the threads 22 of the pin 12 are positionedin the central passageway 58 of the sheath 40 because the distance 140is greater than the distance 36 defined between the distal edge 30 ofthe head 16 and the proximal edge 24 of the threads 22.

As shown in FIG. 7, the user may align the distal tip 20 of the pin 12with a guide pin hole 150 of a surgical instrument such as, for example,femoral cutting block 152, to be secured to the patient's bone 154. Inother embodiments, the surgical instrument may be a tibial cuttingblock, a sizing block, gauge, or other surgical instrument. The user maythen advance the distal tip 20 into the hole 150 and into contact withthe patient's bone 154. As described above, a surgical drill or otherrotary power tool may be attached to the drive shank 46 to rotate thedriver 14 (and hence the fixation pin 12) to screw the pin 12 into thepatient's bone 154. As the driver 14 is rotated about its axis 50, thepin 12 advances into the patient's bone 154, and the distal end 62 ofthe sheath 40 is advanced into contact with the cutting block 152, asshown in FIG. 9.

When the distal end 62 of the sheath 40 contacts the cutting block 152,further movement of the driver 14 toward the patient's bone 154 isprevented. However, continued rotation of the driver 14 causes the pin12 to continue to advance into the patient's bone 154. As the pin 12advances, the head 16 of the pin 12 is advanced distally, away from thesocket 64. With continued rotation of the driver 14, the head 16 isadvanced out of engagement with the socket 64. The sheath 40 is sized sothat the head 16 is advanced out of engagement with the socket 64 toprevent the user from applying too great a torque to the pin 12.

If the user desires to further tighten the pin 12 or remove the pin 12,the user may depress the locking tab 76 by applying a force in thedirection indicated by arrow 156 in FIG. 6. When the locking tab 76 isdisengaged from the slot 78, the user may advance the elongated shaft 42along the longitudinal axis to the full torque position 72 shown in FIG.7. When the user releases the locking tab 76, the lever 120 urges thetab 76 back into the slot 78, as shown in FIG. 7. In full torqueposition 72, the distal end 62 of the elongated shaft 42 (and hence thesocket 64) is positioned adjacent to the distal opening 54 of the sheath40 such that a distance 160 is defined between the opening 54 and thedistal end 62 and socket 64 of the elongated shaft 42. The distance 160is less than the distance 36 defined between the distal edge 30 of thefixation pin head 16 and the proximal edge 24 of the threads 22 suchthat the user may apply the full torque of the surgical drill to thefixation pin 12. In that way, additional torque may be applied to thepin 12 to further tighten the pin or remove the pin 12 from the bone.

To return the elongated shaft 42 to the controlled-torque position 70,the user may pull on the shank 46 as indicated by arrow 162. The arm 130of the lever 120 slides along the inner wall 112 of the elongated shaft42 until it reengages the distal-facing surface 138 in thecontrolled-torque position 70.

While the disclosure has been illustrated and described in detail in thedrawings and foregoing description, such an illustration and descriptionis to be considered as exemplary and not restrictive in character, itbeing understood that only illustrative embodiments have been shown anddescribed and that all changes and modifications that come within thespirit of the disclosure are desired to be protected.

There are a plurality of advantages of the present disclosure arisingfrom the various features of the method, apparatus, and system describedherein. It will be noted that alternative embodiments of the method,apparatus, and system of the present disclosure may not include all ofthe features described yet still benefit from at least some of theadvantages of such features. Those of ordinary skill in the art mayreadily devise their own implementations of the method, apparatus, andsystem that incorporate one or more of the features of the presentinvention and fall within the spirit and scope of the present disclosureas defined by the appended claims.

1. A method of attaching a surgical instrument to a patient's bone, themethod comprising: positioning the surgical instrument in a desiredlocation relative to the patient's bone, inserting a head of a bonefixation pin through a distal opening of a fixation pin driver into asocket defined in an elongated shaft of the fixation pin driver,positioning a threaded distal end of the bone fixation pin in a guidehole defined in the surgical instrument, rotating the fixation pindriver to thread the bone fixation pin into the patient's bone, engaginga distal end of the fixation pin driver with an outer surface of thesurgical instrument, operating a locking mechanism of the fixation pindriver to release the elongated shaft of the fixation pin driver formovement relative to an outer sheath of the fixation pin driver thatincludes the distal end of the driver, and rotating the fixation pindriver and advancing the socket of the fixation pin driver toward thedistal opening of the fixation pin driver to further thread the bonefixation pin into the patient's bone.
 2. The method of claim 1, furthercomprising securing a proximal end of the elongated shaft to a surgicaldrill.
 3. The method of claim 1, wherein the surgical instrument is acutting guide block.
 4. The method of claim 1, further comprisingengaging an annular flange of the bone fixation pin with the outersurface of the surgical instrument after advancing the socket of thefixation pin driver toward the distal opening of the fixation pindriver.
 5. The method of claim 1, further comprising moving the socketof the fixation pin driver away the distal opening of a fixation pindriver until a biasing element causes the locking mechanism to engagethe outer sheath and prevent movement of the elongated shaft.